Oklahoma tornado surprisingly quick forming and long lasting

Los Angeles Times : The Oklahoma City suburb of Moore has been hit by major tornadoes in 1999, 2003, and now 2013. Weather experts believe that the tornado strikes are just a case of statistical bad luck and that the town’s specific location does not make it especially prone to storm formation. However, the middle part of the US is called Tornado Alley because it is the meeting area of warm, humid air from the Gulf of Mexico to the south and cool, dry air from the Rocky Mountains to the west. The two masses of air create swirling winds that spawn massive supercell thunderstorms. On the day of the most recent tornado, a lot of warm, moist air lay near the ground, with a quick drop in temperature as altitude increased. And a nearby dissipating storm may have caused a surge of low-level air that fed the circulation driving the storm. The resulting storm developed incredibly quickly, with the supercell forming in 10 to 15 minutes. The tornado itself lasted for 50 minutes and traveled for 20 miles, whereas most tornadoes last less than 10 minutes. Weather scientists hope to use extensive radar measurements and other observational data to try to determine why the tornado formed so quickly.